Boring head arms expansible in fixed ratio



Nov. l5, 1966 A. P. BROWN 3,285,565

" BORING HEAD ARMs EXPANSIBLE IN FIXED RATIO Filed oct. 11, 196s 2 sheets-sheet 1 I L 29. INVENTOR: l Amos P. BROWN aoT* f' ATTORNEY Nov. 15, 1966 A. e. BRQWN BORING HEAD ARMS EXPANSIBLE IN FIXED RATIO 2 Sheets-Sheet 2 Filed OGL 11, 1963 mw 0N v .m Tw N N o R E R 0 l VB T 4 3 WP. M 2 S 2 O o0 M 2 f 2 MW@ A M f w ,.4 l, f W 2 6 8 2 2 2 9 2 1|. K@ A 3 M n.5u

FIG.5.

United States Patent O 3,285,665 BORING HEAD ARMS EXPANS'IBLE IN FIXED RATIO Amos P. Brown, Mercer, Pa., assignor to Joy Manufacturing Company, Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct. 11, 1963, Ser. No. 315,656 3 Claims. (Cl. 299-80) This invention relates to a mining machine and more particularly to a boring arm type mining machine having diametrically extensible boring arms for mining different seam thicknesses of coal or other mineral.

Mining machines having extensible boring arms are well known in the art and have been successful under most conditions of operation. However, under conditions where it is desired to change from one seam thickness being mined to another seam thickness to be mined only the outermost bit carriers of such extensible arms are mechanically or hydraulically extensible to meet the changed mining conditions. Leaving the intermediate bit carriers in their original positions when the outermost carriers are extended to mine a thicker seam of coal results in the development of a thick ring-like core of unmined coal between the bit paths of the outermost and intermediate carriers which is not readily removed by the core breaking action of the carriers.` In boring machines of the prior art this situation was met by unbolting the intermediate carriers and moving them outwardly to new positions where they were rebolted to produce la satisfactory` thickness. of core when mining was recommended.

Such manual relocation of the intermediate bit carriers requires that the machine be backed away from the face and the mining cycle interrupted for the period of time necessary for such relocation. These actions are expensive in terms of machine time lost and man hours consumed.

The boring machine ofthe present invention is equipped with unique boring arms in which extension of the outermost bit carriers t-o accommodate a thicker seam of coal is accompanied by an outward motion of the intermediate bit carriers at a fixed ratio relative to the motion of the outermost carriers. This ratio being desirably of the order of 2 to 1 so that increased core thickness is shared between the outer core and an inner core between the ker'fs formed ,by the intermediate and inner bit carriers.

`carriers and extensible intermediate bit carriers.

It is a specific object of this invention to Vvprovide a new and improved boring machine having boring arms provided with central, inner, intermediate and outermost bit carriers of which both the intermediate and outermost bit carriers are mechanically or hydraulically extensible according to a ratio of approximately 2 to l as between the extensive motion of the outermost carriers and the extensive motion of the intermediate carriers.

These and other objects and advantages of `this.invention will become more readily apparent upon consideration of the following description and drawings in which:

FIG. 1 is a front elevational View partially in section of a ratio extensible boring arm constructed according to the principles of this invention;

FIG. 2 is a sectional view taken substantially on line 2 2 of FIG. 1;

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FIG. 3 is a sectional view taken substantially on line 3-3 of FIG. l;

FIG. 4 is an enlarged sectional view taken substantially on line 4-4 of FIG. 3;

' FIG. 5 is a side elevational view of a mining machine provided with boring arms constructed according t0 the principles of this invention located in a portion of a mineral vein shown in vertical section;

FIG. 6 is a side elevational view partly in section of a bore arm constructed according to the principles of this invention showing la method of mounting such boring arm on the mining machine of FIG. 5 and one method of controlling the extension and retraction of the boring arms of this invention;

FIG. 7 is a fragmentary, enlarged elevational View taken substantially on line 7--7 of FIG. 5.

In FIG. 5 there is shown a boring machine 10 supported and rendered movable over a surface by crawler type traction means 12 orbitally driven by suitable electro-hydraulic power means (not shown). The crawler means 12 support a main frame 14 which in turn supports a pair of transmissions 16 mounted on a forward portion of the frame 14 and forwardly extending therebeyond in parallel, horizontally spaced relationship, equidistant from the longitudinal center line of the machine. Each transmission 16 is powered by suitable electric motor means 16 and is provided with a forward extending hub portion 17 in which is suitably rotatably mounted an elongated, hollow boring arm drive shaft 18, partially shown in FIG. 6, extending forwardly beyond the hub portion 17 and rigidly secured in keyed relationship with a rearwardly extending hub portion 21 of a boring arm constructed according to the principles of this invention and generally indicated at 20.

Each boring arm 20 is provided with a plurality of forwardly extending radially spaced, bit carriers hereinafter described as central bit carriers 24, inner bit carriers 26, intermediate bit carriers 28 and outer bit carriers 30, respectively, each of which is provided with a plurality of cutter bits 31 of a type well known in the art vfor attacking and disintegrating a mineral vein. The central bit carrier 24 and the inner bit carriers 26 are rigidly mounted upon an elongated hollow, generally cylindrical, main body portion 34 of the boring arm 20 having a central axis normal to the axis of the drive shaft 18. The main body portion is rigidly secured to or formed integral with the hub portion 21 and extends equally radially outward therefrom. The intermediate bit carriers 2S and the outer bit carriers 30 are rigidly secured to radially extensible cylindrical members 27 and 29 respectively (see FIG. 1) closely slidably received in suitable bores in suitable end caps 35 and 61 respectively. The end caps 35 are rigidly removably secured in uid tight relationship with the ends of the main body portion 34 by a plurality of threaded members such as cap screws 36. The main body portion'34 extends radially outwardly from the hub portion 21 to form hollow cylindrical arms 37 having coaxial inner cylindrical surfaces 38. Rigidly secured to the bottom surfacel of the end caps 35 and extending inwardly Within the cylindrical surface 38 in keyed relationship therewith is a plurality of spacers 39 having yarcuate outer surfaces conforming to the inner surface 38 and planar inner surfaces enclosing a polyhedral space shown as having a square cross section but not limited to such contiguration since any polygonal cross section would be suitable to slidably non-rotatively receive a radially extended bottom portion 40 of the cylindrical member 29 to render it slidably extensible but non-rotatable within the arm 37.

The cylindrical member 29 has an axial `bore 41 extending therethrough having a counterbore in its bottom end portion and a generally cylindrical internally threaded tion to the arm 37.

force member 42 rigidly removably secured within the bottom end portion of the bore 41 in keyed relationship therewith to prevent rotation of the force member 42 with rela- Rigidly secured to or integrally formed with the upper surface of the force member42 is an elongated tubular portion 43 extending upwardly through the bore 41 to a point inwardly adjacent its top end as seen in FIG. 1. The top end portion of the tubular portion 43 is internally threaded and is threadedly engaged with a threaded portion of a force collar 45 which has an upper surface coplanar with the top end surface of the tubular member 29 -and is secured in such relationship by a plurality of threaded retaining members such as cap screws 46. An elongated generally cylindrical force rod 47 extends axially through the main body portion 34 for the full length thereof and has elongated threaded end portions threadedly eng-aged with the two force members 42 oppositely displaced from the axis of the drive shaft 18 with the upper force member 42 and the upper end of the rod 47 as shown in FIG. 1 having right hand internal and external threads respectively and the lower force member 42 and the lower end of the rod 47 as seen in FIG. 1 having left hand internal and external threads respectively so that rotation of the rod 47 in a direction from right to left as seen in FIG. 1 will cause both force members 42 to be moved radially outwardly from the axis of the driveshaft 1S while a reverse rotation will cause the force members 42 to be biased inwardly by the threaded action. A central portion of the rod 47 is rotatively received and positioned by a suitable support member 48 rigidly mounted in and extending transversely across an enlarged central portion 44 of the main body portion 34. Between the upper force member 42 as seen in FIG. 1 and the support member 48 a splined portion of the force rod 47 is provided with an internally splined spur gear 49 which meshes with a gear 504 for a purpose to be hereinafter described. Between the lower force member 42 as seen in FIG. l and the support member 48 another splined portion of the force rod 47 is provided with a combination spur gear and bevel gear 51 the spur gear portion of which meshes with a similar spur gear 50 such -as hereinbefore mentioned. The gears 49 and 51 are rigidly removably secured to the force rod 47 by suitable threaded retaining elements such as bearing locknuts 53 threadedly engaged with the rod 47. The rod 47 is restrained from axial movement by suitable thrust bearings 54 slidably mounted on the rod 47 and engaged between the support member 48 andthe gears 49 and 51, respectively.

Referring now to FIG. 6 it will be seen that the bevel gear portion of the combination gear 51 meshes with a bevel gear 52 mounted on .a spline end portion of an elongated shaft 57 rotatably mounted and journaled in the central bore of the hollow driveshaft 18 'being coaxial therewith and extending rearwardly through .t-he full length of the shaft 18 to .a point where the shaft 57 is provided with driving means (not shown) by which extension and retraction of t-he outer bit carriers 30 can |be controlled.

Referring again to FIG. 1 the force rod 47 is provided at each end with a reduced diameter threaded portion threadedly receiving a nut 59 and slidably receiving a washer 59 which together retain a :suitable antfriction bearing 58', adapted to receive and transmit axial thrust,

rigidly removably mounted on the force rod 47. The

bearing 58 is of larger outside diameter than the threaded portion of the force rod 47 so that as long as the bearing 58 is held in place the force member 42 cannot be extended beyond a predetermined desirable outward position since the upper surface of the force member 42 will come into abutting engagement with the bottom surface of the bearing 58.

The main body portion 34 is also provided with angu- Alarly disposed hollow, generally cylindrical auxiliary body portions 60 extending from the enlarged central portion of the body portion 34 substantia-lly radially outwardly at an `acute angle with respect to the axis of the main body portion 34. 'Ihese body portions 60` are each provided in a manner just described for the arm portions 37 with an axially disposed threaded force rod 62 rotatably supported by the support member 48 and connected to the cylindrical member 27 so that rotation of the gear 50 rigidly mounted on the force rod l62 at a splined portion thereof will rotate the force rod 62 and cause extension and retraction of the cylindrical member 27 and the attached intermediate bit carriers 28 `simultaneously with the extension and retraction of the outer :bit carriers 30 just described. A ratio is established between the gears 49 4and 50 which in conjunction with a difference `in the pitch of threads on the for-ce rods 47 and 62 Igives a ratio of extension and retraction of approximately 2:1, the outer bit carriers 30 traveling twice as far as the intermediate 'bit carriers 28 in the radial directions. It is to be noted .that the cylindrical member 27 also has a bottom end portion 63 with a square cross section to prevent rotation of the cylindrical member 27 and consequently of the intermediate arm 28 about the axis of the auxiliary body member 60;

In FIG. 1 there is also shown a suitable thrust bearing 55 slidably mounted on the force rod 62 and engaged between the gear 50 and the support'48 to prevent axial motion of the force rod 62.

It is to be noted that the `outer bit carrier 30 and the intermediate bit carriers 28 are rigidly removably secured on the outer end of the cylindrical members 29 and 27, respectively, through the use of key and keyway relationships (not shown) and a plurality of threaded retaining members such as cap screws 32 (see FIG. 6). It is further to be noted that the central bit carrier 24, the inner bit carriers 26 and the intermediate bit carriers 28 have backwardly outwardly sloping portions 24', 26' and 28', respectively, to perform a core breaking action as hereinbelow more fully described, and that the outer bit carriers 30 are provided with outwardly extending clearance bits 31 along their outer surface as is known.

The mining machine 10 as shown in FIG. 5 also incorporates an independently adjustable roof forming device such as a loop cutter 11 which forms a substantially horizontal ceiling line 13 as the machine 10' advances in cutting and removing coal or other mineral from a mineral vein in a manner well known in Ilthe art. As shown in FIG. 5 the mining machine 10 also has a rearwardly extending swing conveyor 15 to deliver coal or other mineral removed from the mineral vein to a shuttle car or other delivery device for carrying away the mined mineral as is known. The right band end of FIG. 5 represents a portion of a mineral vein 65 depicted as a vertical cross section taken on a plane through the axial centerline of one of the boring arms showing a cross sectional view of the face pattern developed by the one Iof the boring arms as the mining machine 10 advances into the seam in normal operation. The bits 31 on the central bit holder -form a blind bore 64, the bits 31 on the inner bit carrier l26 form a circular kerf 66 with a ring shaped land or core 64 formed between the Ibore 64 and the kerf 66. In like manner the bits 31 on the intermediate bit carrier 28 form a circular kerf 68 leaving a circular core 67 between the kerf 66 and 68. In an entirely similar manner the outermost bit carrier 30 forms the kerf 70l and a circular core 469 between the kerf 70 and the kerf 68. The ceiling line 13 is formed as hereinbefore mentioned by the roof cutter 11 forming a kerf 72 with a curved core 71 between the kerfs 70 and 72. A front elevational view of a portion of such face pattern is shown at an enlarged scale in FIG. 7, the cores being shown in section and the grooves shown plain for purposes of greater clarity.

The operation of the mining machine 10 of'this inven- Vtion is entirely conventional at any lgiven seam height and of a type well known in the art. Hence, such an operation will be described only `sufficiently to establish the ter-minology being used and the conditions of operation `As the mining machine of this invention advances against a vertical mine face (to the right as seen in FIG. first contact with the face is made by the bits on the central bit carrier 24 which begin to form the bore `64 by cutting and breaking out the coal therein. After a small amount of the bore `64 has been formed the bits on the inner bit carrier 26 contact the face and begin to form the circular kerf 66. As the advance of the machine continues, the rest of the bits come in contact with various portions of the coal face with the result as illustrated. When the bore 64 has been sufiiciently deepened the outwardly slanting core breaker portion 24 contacts the coal in the core 64', and pushing it outwardly, breaks coal out of the core 64 so that it falls to the floor and is ca-rried away in the usual manner. In like manner further advance of thev machine brings the core breakers 26 and 28 into action pushing 4outwardly -on the coal in the cores 67 and 69, respectively, causing similar breaking action as a part of the mining procedure. It is t-o be noted that all of the breaking action is outwardly directed since inward breaking of the ring cores or lands would .be opposed by the arch effect of the ring of coal and as a consequence there are no core breakers on the outermost bit carriers 30'. Experiment has shown that it is desirable to maintain the thickness of the cores 67 and 69 in a ratio such that there is approximately the same amount orf coal in the core 67 as in the core `69. Since the diameter of the core 69 is so much greater than the diameter of the core `67 it is desirable for the core l67 to be of lgreater radial thickness than the core 69. Consequently, boring arms are built an-d adjusted to produce the desired ratio -of radial thick- `nesses and such machines have been successfully applied to the art of coal mining and other mineral extraction.

When it is desired to mine coal to a different height than the maximum height illustrated by FIG. 5 the shaft 53 is rotated in a proper direction to cause the outerm-ost bit car-riers 30 to be partially retracted, for example a distance of six inches, resulting in a one foot reduction in the diameter of the boring arms and consequently of the face pattern Iformed. With the devices of the prior art such retraction of the boring arms to a new boring arm diameter would reduce the radial thickness -of the core 69 by a total of six inches with the result that the desired ratio of radial thicknesses hereinabove described would be lost and ineflicient operation would be the result. With the boring arms of the present invention retraction of the outermost bit carriers 30 by a distance of six inches results in concommitant retraction of the intermediate bit carriers 28 a distance of three inches with the result that the radial thickness lof the core `69 is reduced by three inches and at the same time the radial thickness of the core 67 is reduced by the same amount with the result that the desired ratio -of radial thicknesses is very nearly the same at the reduced diameter setting of the boring arm-s as it was at the original setting.

The above described rati-o motion is illustrated in FIG. 1 by the difference in radial extension between the solid outlines o-f the cylindrical members 27 and 29 and the broken line Ioutlines of these members indicated as 27 and 29', respectively. The numeral 30 indicates the extended position of the outer bit carrier 30, likewise in broken line outline, while in similar manner the numeral 28" indicates the extended position of the intermediate bit carrier 28.

It is to be appreciated that the above described ratio of radial carrier m-otion can be any desired value as dictated by mining conditions for which the machine is being built. It is further to be appreciated that such ratio movement can be achieved by using hydraulic actuation, without departing from the scope of this invention.

Maintenance of the desired thickness ratio for the cores 69 and 67 is so important that in machine-s of the prior art the intermediate bit carriers such as carriers 28 are either changed or moved to a different location to main- 6 tain such desired thickness ratio. Since no machines of the prior art make provision for mechanically or hydraulically actuated ratio movement such as above described such moving of the intermediate bit carriers, in prior art machines, involves moving the machine away from the face and unbolting the intermediate carriers to allow them to be removed and reattached in a new location.

The advantages resident in the boring machine of this invention a-re obvious when it is realized that such ratio adjustment is accomplished merely by rotating the shaft 53 in relation to the driveshaft 18 even while mining operati-ons continue without interruption. Such non-interrupting adjustment is especially important in mines where seam thickness varies as the mining operation advances and it is in such situations that the advantages inherent in the boring arms of this invention become most apparent. These advantages include maintenance of core thickness ratio at different bore diameters for most efiicient mining; mechanically or hydraulically actuated ratio adjustment of outermost and intermediate carriers with no interruption of mining operation; and adaptability of the boring machine to Iseams yof varying thickness.

It is to be appreciated that, although the operation of the boring machine 10 has hereinabove been described as applied to the mining of coal, the principles of this invention apply equally well t-o the mining of other materials and the production of bores in earth strata for purposes other than mining.

A preferred embodiment of this invention having been described and illustrated it is to be realized that variations therein may be made without departing from the broad spirit and scope of this invention. It is therefore respectfully requested that this invention be interpreted as broadly as possible and be limited only by the prior art.

I claim:

1. A mining machine boring arm comprising: a hub portion, at least one radially extending main arm having an elongated guideway therein, said main arm having a bit carrying outer end portion remote from said hub portion, said end portion being radi-ally movable with respect to said hub portion along said guideway, an elongated auxiliary arm extending outwardly from said hub portion at an acute angle to said main arm, said auxiliary arm having an elongated longitudinal guideway therein, said auxiliary arm having a bit carrying end portion remote from said hub portion, said auxiliary arm end portion being movable along said `auxiliary yarm guideway with respect to said hub portion, selectively operable first actuating means to provide a given amount of said radial motion to said outer end portion of said main arm, second actuating means to provide an amount of said radial motion less than said given amount to said end portion of said auxiliary arm, ratio fixing means connecting said rst actuating means to said second actuating means to maintain the said radial motion of said main arm outer end portion in a predetermined fixed ratio to the said radial motion of said auxiliary arm end portion.

2. A mining machine boring larm comprising: a hub portion, at least one radially extending main arm having an elongated radial bore therein, s aid main arm having a bit carrying outer end portion remote from said hub portion, said end portion being telescopingly movable along said bore, an elongated auxiliary larm extending outwardly from said hub portion at an acute angle to said main arm, said auxiliary arm having an elongated longitudinal bore therein, said auxiliary arm having a bit carrying end portion remote from said hub portion, said auxiliary arm end portion being telescopingly movable along said auxiliary arm bore, selectively operable first actuating means to provide a given amount of said telescoping motion to said outer end portion of said main arm, second actuating means to provide an amount of said telescoping motion less than said given amount to said end portion of said auxiliary arm, ratio fixing means connecting said first actuating means to said second ractuating means to maintain the said motion of said main arm outer end portion in a predetermined xed ratio to the said motion of said auxiliary arm end portion.

3. A mining machine boring arm comprising: a hollow hub portionrotatiable about an axis, two radially extending main arms in diametrically opposed relationship, said main arms having `coaxial radial bores extending from said hollow hub portionv radially outward through said main arms respectively, two elongated auxiliary arms extending outwardly from said 4hub portion at an acute angle to said main yarms respectively, each of said auxiliary arms having a longitudinal bore extending therethrough, said auxiliary varm bores having axes intersecting the axis of said main arm radial bores, but carrying means telescopingly movably attached to each of said arms respectively, said bit carrying means having a bit carrying outer end portion and Ia radially inwardly extending elongated slide surface portion, said slide portions being slidably non-rotatably received in said bores respectively, each of said bit :carrying means having a longitudinal threaded CTI bore therein, elongated externally threaded actuating means threadedly engaged with each of said bit carrying means, power means for rotating said main arm actuating means, gear means transmitting rotative motion from said main arm actuating means t0 said auxiliary -arm actuating means at a predetermined fixed ratio of rotative motion.

References Cited by the Examiner UNITED STATES PATENTS 1,467,513 10/ 1923 Starr et al. 299-61 X 2,765,156 10/ 1956 Cartlidge 299-80 2,822,150 2/1958 Muse et al 175-269 X 2,868,527 1/1959 Von Stroh et al. 299--59 2,879,049 3/ 1959 Poundstone 299-61 X 2,937,859 5/1960 Jackson 299*86 X 2,998,964 9/1961 Morlan 299-80 3,108,788 10/1963 Allimann 299-57 ERNEST R. PURSER, Primary Examiner. 

1. A MINING MACHINE BORING ARM COMPRISING: A HUB PORTION, AT LEAST ONE RADIALLY EXTENDING MAIN ARM HAVING AN ELONGATED GUIDEWAY THEREIN, SAID MAIN ARM HAVING A BIT CARRYING OUTER END PORTION REMOTE FROM SAID HUB PORTION, SAID END PORTION BEING RADIALLY MOVABLE WITH RESPECT TO SAID HUB PORTION ALONG SAID GUIDEWAY, AN ELONGATED AUXILIARY ARM EXTENDING OUTWARDLY FROM SAID HUB PORTION AT AN ACUTE ANGLE TO SAID MAIN ARM, SAID AUXILIARY ARM HAVING AN ELONGATED LONGITUDINAL GUIDEWAY THEREIN, SAID AUXILIARY ARM HAVING A BIT CARRYING END PORTION REMOTE FROM SAID HUB PORTION, SAID AUXILIARY ARM END PORTION BEING MOVABLE ALONG SAID AUXILIARY ARM GUIDEWAY WITH RESPECT TO SAID HUB PORTION, SELECTIVELY OPERABLE FIRST ACTUATING MEANS TO PROVIDE A GIVEN AMOUNT OF SAID RADIAL MOTION TO SAID OUTER END PORTION OF SAID MAIN ARM, SECOND ACTUATING MEANS TO PROVIDE AN AMOUNT OF SAID RADIAL MOTION LESS THAN SAID GIVEN AMOUNT TO SAID END PORTION OF SAID AUXILIARY ARM, RATIO FIXING MEANS CONNECTING SAID FIRST ACTUATING MEANS TO SAID SECOND ACTUATING MEANS TO MAINTAIN THE SAID RADIAL MOTION OF SAID MAIN ARM OUTER END PORTION IN A PREDETERMINED FIXED RATION TO THE SAID RADIAL MOTION OF SAID AUXILIARY ARM END PORTION. 